...Spinoza became aware of this in a way that made him show his true colours (to the annoyance of his critics, who systematically attempt to misunder… - Benedictus de Spinoza

...Spinoza hit the nail on the head with his paradoxical proposition: God is an extended, that is, material being. He found, at least for his time, the true philosophical expression for the materialistic tendency of the modern era; he legitimated and sanctioned it: God himself is a materialist. Spinoza's philosophy was religion; he himself was an amazing man. Unlike so many others, Spinoza's materialism did not stand in contradiction to the notion of a non-material and anti-materialistic God who also quite consistently imposes on man the duty to give himself up only to anti-materialistic, heavenly tendencies and concerns, for God is nothing other than the archetypal and ideal image of man; what God is and how he is, is what man ought to be or wants to be, or at least hopes to be in the future. But only where theory does not belie practice, and practice theory, is there character, truth, and religion. Spinoza is the Moses of modern free-thinkers and materialists.

Spinoza is the clear and luminous side of Modern philosophy. He is the negation of bourgeois mediation and of all the logical, metaphysical, and juridical fictions that organize its expansion. He is the attempt to determine the continuity of the revolutionary project of humanism. With Spinoza, philosophy succeeds for the first time in negating itself as a science of mediation. In Spinoza there is the sense of a great anticipation of the future centuries; there is the intuition of such a radical truth of future philosophy that it not only keeps him from being flattened onto seventeenth-century thought but also, it often seems, denies any confrontation, any comparison. Really, none of his contemporaries understands him or refutes him.

[Jérome Skalski's question: Wasn't Spinoza also a thinker of radical democracy? Philosophically, was Althusserian Marxism also a return to Spinoza?] Althusser admired the Spinoza of the Theological-Political Treatise, but that was not the aspect that interested him the most. You are absolutely right to say that Spinoza's thought is a radically democratic thought. This is a dimension that has come to the forefront for a while now, and which has been appropriated by a broad variety of philosophers some of whom effectively come from a Marxist background. However, this was not the aspect or dimension that interested Althusser. Not because he was hostile towards it, but because he fundamentally thought that radical democracy was a transition, an intermediary stage towards the dictatorship of the proletariat. From this point of view, he was a very orthodox Marxist. The dimension that he emphasized in Spinoza concerned the theory of ideology. With Spinoza, there is the first great materialist critique of ideology. Althusser defended a paradoxical thesis. I understand that it forcefully shocked many Marxists at the time but, on the other hand, it was very attractive to certain people among us. This idea was that the concept of ideology was the fundamental aspect of Marx's theoretical revolution: not only the critique of bourgeois ideology, but the critique of ideology in general. To Althusser, this also appeared to be an important point within the debates internal to Communism at the time, in that it was dominated by the ideological complex he called humanism and economism. He thought that the Marxist tradition was weak on the question of ideology and that Marx, even if he possessed the genius to invent the concept, had had a very bad analysis of it. In Spinoza, he found the elements for a materialist theory of ideology that was neither Feuerbachian or Hegelian, and was not attached to a philosophy of history or to the concept of an alienation of man or a human essence. All of this paired very well with what was called Althusser’s scientism, such as it was expressed in the idea of the epistemological break and led to his proximity with structuralism. Althusser quickly criticized these positions in his Elements of Self-Criticism.